A　novel　ID　molybdenum(V)　phosphate　with　mixed-valence　cobalt　coordination　cation,　Co-II[Mo6O12(OH)(3)(PO4)(HPO4)(3)](2)[Co-III(H2O)　(2,2＇-bpy)(2)](2)[Co-3(II):　(OH),(H2O)(4)]　center　dot　2H(2)O　(1),　has　been　synthesized　by　hydrothermal　and　characterized　by　single　crystal　X-ray　diffraction.　The　title　complex　crystallizes　in　the　triclinic　system,　space　group　Pi,　with　a　=　12.8779(6),　b　=　13.6862(10),　c　=　15.1111(8)　angstrom,　alpha　=　97.141(2)degrees,　beta　=　99.1360(10)degrees,　gamma　=　116.719(4)degrees.　The　structure　of　the　title　polyoxometalate　is　based　on　CoII[Mo6O12(OH)(13)(PO4)(HPO4)(3)](2)　clusters　connected　together　via　[Co-3(II)(OH)(2)(H2O)(4)]　trimers　to　give　a　new　unusual　ID　chain-like　along　the　c-axis,　where　the　Co[Mo6P4](2)　cluster　unit　is　bonded　by　[Co-III(H2O)(2,2＇-bpy)(2)]　unit.　(c)　2005　Elsevier　B.V.　All　rights　reserved.